High-quality OLED displays now enabling integrated thin and multichannel audio

Right.

It's a way of putting speakers behind a display, which will probably be useful. This may improve bass response in laptops, because the speaker area is larger.

Audi somewhat did this with the display in the Q8 E-Tron. I don’t recall if the display is OLED, but it has excellent haptics.

A laptop improvement I'd love would be a haptic keyboard. You could then make the entire laptop waterproof as well as do keyboard reconfiguration for certain tasks.

I always though Apple's Touch Bar was some kind of entry point into that idea but it wasn't, wasn't useful, and just died.

Yeah, I don’t know, I suspect you’re right. I know that 25 years ago there were big flat speakers thay drove sound with little holes. Those things could only handle high ends despite being very large themselves. But I know that with DSP you can treat an array of microphones as a single microphone, and the diameter of the array sort of dictates the size of the microphone. Speakers and mics tend to sort of be opposites, in that you can drive or be driven by either. For years I’ve wanted to build a wall of cheap speakers and experiment with this. I suspect I’d find out what we already know, which is to get deep frequencies you have to move a lot of air, and an array of small piezos can never move a lot of air…

That said, it might matter a lot what the substrait was. If it was light and flexible, you could maybe get all the piezos to move it in a way to get a very deep frequency. You could probably get deeper frequncies than the power output of the piezos by taking advantage of the resonance frequency of the material. But you’d be stuck with that one frequency, and there’d be a tradeoff in response time

A proper telescreen is not the one you watch and listen to, but the one that watches you and listens to you, %little_brother%

Technically yes, piezo cells are reversible, just like about anything that can be used to emit sound. You can use the array for programmable directionality as well.

Good point, piezos do also generate voltages when deformed, so this could conceivably be run in reverse... Microphone arrays are already used for directional sound detection, so this could have fun implications for that application given the claimed density of microphones.

These are a thing: https://hackaday.com/2019/10/26/building-the-worlds-best-dml...

You could always have a separate speaker for low frequencies. Low frequency sound tends to be perceived with less of a directional component, so if you have nice directionality of the highs and a single source for the lows, that's pretty acceptable. Removing the need to handle highs might make it easier to put together a speaker for the lows in the confines of a modern flat screen.

Good find - the first video is a frequency sweep, video 2 has some music.

Edit - I'm not sure that's the same thing? The release talks about pixel based sound, the linked paper is about sticking an array of piezoelectric speakers to the back of a display.

edit 2- You're right, the press release is pretty poor at explaining this though. It is not the pixels emitting the sound. It's an array of something like 25 speakers arranged like pixels.

https://www.eurekalert.org/news-releases/1084704

This technology literally sounds like a terrible idea. Why do I want to hear one drummer's drum over the others?

https://advanced.onlinelibrary.wiley.com/action/downloadSupp...

I think you're trying to make an argument similar to those arguing against "retina" displays, i.e. there is some minimum perceptual angular resolution for sound, so information finer than that is pointless? I think you're either underestimating the perceptual resolution or assuming a very small screen at a large distance.

I think that kind of resolution is good enough to overlap a lot of task focused screen fields of view. I have experienced a pretty clear "central" sound stage within 30-45 degrees or so with regular stereo speakers. That field can imply a lot of subtle positioning within it, not even considering wild panning mixes. I'm talking about the kind of realistic recording where it feels like a band in front of you with different instruments near each other but not colocated, like an acoustic ensemble. Obviously you cannot shrink this down to a phone at arm's length or a small embedded control screen and still have the same amount of spatial resolution crammed into a very narrow field.

When I sit with a 14" laptop at a normal distance for typing, it is also easy to distinguish tapping sounds along the screen. I just did a blind test by closing my eyes and having my wife tap the screen with a plastic pen. The interesting question to me, though, is whether that is just perception via the binaural sense, or really incorporating some intuition about the screen's structure. It's response to a tap does clearly vary by distance from bezels and hinges...

If you get enough, you might be able to do some really interesting things using it as a phased array

Not niche at all. You could have a phone for example that plays sounds from areas of the screen where they originate. Key presses, buttons, notification pop ups, etc.

Theoretically, any frequency can be produced by the interference of ultrasonic waves, but the amplitude is questionable, given that these emitters are embedded into a thin substrate.

Probably similar to antennas — using phase shifting and interference.

I've got a Sony Bravia with similar technology for a few years now (it uses small actuators instead of generating from the oled itself, but the vibrations will be the same) and it's still sounding fantastic after daily use and a couple of moves.